The construction industry, as with many other industries, is always endeavouring to improve efficiency in construction techniques. Therefore, novel construction techniques that can achieve the same task and to the same standard as conventional techniques, but in a shorter time, are appealing. Alternatively or additionally, if fewer workers are required to complete the same task, labour costs can be reduced, thus increasing profits and/or improving competitiveness.
Other important considerations in the construction industry are workplace health and safety issues. Whilst improved efficiency is sought after, this should not be at the expense of the health and safety of workers.
Regarding the construction of buildings, Japanese patent application nos. 04336331, 10008071 and 10008072, all in the name of Sekisui House Ltd, disclose a construction method and system for building a house in which part of a roof and an external facing of a first or second floor are completed at ground level, for example, on a concrete foundation. A plurality of hydraulic cylinders situated on the foundation is coupled to a hydraulic pump and a control unit controls the synchronous lifting of the completed roof part and external facing to a predetermined height. Such a system and method enable the roof structure and external facings to be assembled at ground level, which is safer for workers and avoids the necessity of erecting scaffolding and edge protection. Furthermore, the assembled, elevated roof structure enables construction to continue beneath the roof, thus protecting both workers and building materials from the weather. Additionally, the aforementioned system and method are purported to reduce the completion time for the building.
Whilst the aforementioned system and method address some of the aforementioned efficiency and workplace health and safety issues in the construction industry, the aforementioned system employs complex hydraulic jacks and requires a number of workers to operate the system, particularly with the insertion of additional struts to extend the elevation reach of the jacks. The insertion of struts by workers during the elevation can also be dangerous. Also, the systems and methods employ I-beams as supports, which are heavy and require heavy duty lifting equipment to manoeuvre into position. Furthermore, the hydraulic jacks of these systems and methods are positioned inside the perimeter of the foundation thus requiring additional support around the perimeter. Therefore, additional equipment is required and use of the system requires a certain amount of space that may not be available on many sites. The complexity of these systems and methods adds to the preparation time which can negate the time benefits gained from the elevation process. It is envisaged that at least one working day with four people would be required to complete the elevation using these systems and methods. Another drawback is that temporary bracing of the roof structure would be required, which can damage the roof structure, thus necessitating replacement of the damaged parts. It is likely that replacement of the damaged parts will need to be carried out once the roof structure is at the prescribed height, which requires the scaffolding and edge protection the system and method was designed to avoid.
Further lifting systems, methods and apparatus are disclosed in U.S. Pat. No. 6,027,295 (Geppert et al.), WO 2004/065712 (The Mattamy Corporation), FR 2540543 (Lotti) and JP 10110544 (Kawasaki Heavy Industries Ltd). However, these systems, methods and apparatus all suffer from one or more of the aforementioned problems.
Hence, there is a need for a simplified, improved construction system and method, which retains the efficiency and workplace health and safety benefits of the system and method of the aforementioned prior art.
In this specification, the terms “comprises”, “comprising” or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.